The proton coupled electron transfer and electron transfer reactions of photochemically-prepared, charge-separated biomimetic assemblies is under investigation from both a theoretical and experimental standpoint. A homologous series of biomimetic compounds has been designed that permits a comparative study of electron transfer and proton coupled electron transfer reactions. These experiments permit the role of solvent dynamics, as well as energetics, to be defined for electron transfer rates of the biomimetic donor/acceptor complexes in solvents providing a wide range of dielectric relaxation times, as may be evocative of a protein environment. With the electron transfer chemistry elaborated, a study of proton coupled electron transfer reactions has been initiated on a series of donor/acceptor pairs that are intramolecularly juxtaposed by a cyclic hydrogen bonded network of a dicarboxylic acid dimer or quinhydrone. The effect of proton transfer mediation on electron transfer rates is being assessed in well defined experimental systems, with the goal of elucidating these effects in the biological context. FAB-MS is used to characterize the large porphyrin-based biomimetic assemblies used in both the electron and proton-electron transfer studies.